WO2009096423A1 - Network system, node, packet forwarding method, program, and recording medium - Google Patents
Network system, node, packet forwarding method, program, and recording medium Download PDFInfo
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- WO2009096423A1 WO2009096423A1 PCT/JP2009/051348 JP2009051348W WO2009096423A1 WO 2009096423 A1 WO2009096423 A1 WO 2009096423A1 JP 2009051348 W JP2009051348 W JP 2009051348W WO 2009096423 A1 WO2009096423 A1 WO 2009096423A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/02—Traffic management, e.g. flow control or congestion control
- H04W28/10—Flow control between communication endpoints
- H04W28/14—Flow control between communication endpoints using intermediate storage
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- the present invention relates to a network system, a node, a packet transmission method, a program, and a recording medium, and more particularly to a network system including one core node and a plurality of slave nodes.
- Wireless mesh networks are attracting attention as a backhaul network for low-cost mobile communication infrastructure.
- the wireless mesh network is a technology that can significantly reduce the installation cost required for introducing a mobile communication system by connecting base stations with a dedicated wireless relay, eliminating the need for a wired backhaul line.
- future broadband communications the narrowing of cells is inevitable, and an extremely large number of base stations must be installed, which increases the cost of laying base stations.
- Wireless mesh networks are the only technology that solves this problem.
- the inventors have proposed a periodic intermittent transmission method (hereinafter referred to as “IPT”) that realizes packet relay transmission with high transmission efficiency in a multi-hop network in which a plurality of nodes are arranged. (See Patent Literature 1, Patent Literature 2, and Patent Literature 3).
- IPT periodic intermittent transmission method
- the protocol was designed on the assumption that the upper and lower lines are transmitted in a single lane path. Therefore, when the upper and lower lines are mixed or the lanes are branched, the characteristics are greatly deteriorated.
- IPT in principle, exhibits the maximum effect under a one-dimensionally arranged relay link, but in reality, relay nodes are distributed in two or three dimensions. Therefore, the inventors have devised a technique capable of exerting the effect of periodic intermittent transmission under any network topology by applying route reservation as disclosed in Patent Document 3. However, depending on the route reservation method, overhead for route reservation occurs.
- an object of the present invention is to propose a network system, a node, a packet forwarding method, a program, and a recording medium that realize packet relay transmission with higher relay transmission efficiency in IPT.
- the invention according to claim 1 is a network system including one core node and a plurality of slave nodes, wherein each slave node is a downlink packet transmitted from the core node to another slave node, and a slave A transmission buffer that stores an upstream packet that is a packet transmitted from the node to the core node; a packet that is received from another node; and a packet that is stored in the transmission buffer is transmitted to another node.
- a plurality of communication means in which downlink priority and uplink priority which are two types of priority are set transmission preparation packet selection means for selecting a transmission preparation packet from packets stored in the transmission buffer, and If the transmission preparation packet is the downlink packet, according to the downlink priority, or If the transmission preparation packet is the uplink packet, the communication preparation unit selects one communication unit according to the uplink priority, and causes the selected communication unit to transmit the transmission preparation packet.
- Transmission buffer for storing packets, receiving packets from slave nodes, transmitting packets stored in the transmission buffer to slave nodes, and two types of priority, downlink priority and uplink priority
- a plurality of communication means for which a degree is set, a transmission preparation packet selection means for selecting a transmission preparation packet from the packets stored in the transmission buffer, and one communication means according to the downlink priority, and the selected communication By causing the means to transmit the transmission preparation packet through a transmission standby state, the communication means immediately before the communication means The time of a packet from the time it has finished sending a until the time to transmit the transmission ready packet in which a communication control means for a predetermined time.
- each of the slave nodes includes event generation means for generating an event when a downlink packet is received, and the communication control means of the slave node Is to select one communication means when an event is generated by the event generation means of the slave node.
- the invention according to claim 3 is the network system according to claim 2, wherein the core node periodically transmits a packet to a slave node.
- the invention according to claim 4 is the network system according to claim 2 or 3, wherein the event generation means generates an event when a predetermined number or more packets are stored in the transmission buffer. is there.
- each of the slave nodes includes event generation means for generating an event when a new packet is added to the transmission buffer.
- the communication control means of a node selects one communication means when an event occurs by the event generation means of the slave node.
- the invention according to claim 6 is the network system according to any one of claims 1 to 5, wherein the communication means having the highest uplink priority and the communication means having the highest downlink priority are different. .
- the invention according to claim 7 is the network system according to any one of claims 1 to 6, wherein the communication control unit of the core node has transmitted the packet immediately before on the communication unit.
- the time until the time when the transmission preparation packet is transmitted is a transmission cycle set according to at least one of the slave node that is the transmission destination of the transmission preparation packet and the packet length of the transmission preparation packet.
- the invention according to claim 8 is the network system according to any one of claims 1 to 7, wherein the communication control means of at least one of the core node and the slave node is configured to transmit packets stored in the transmission buffer. If the number does not exceed the predetermined number P NT, the highest-priority communication section is selected, if the number of stored in the transmission buffer packet exceeds P NT, the communication means selected immediately before the highest priority When not a low communication means, the communication means with the next highest priority is selected, and when the communication means selected immediately before is the communication means with the lowest priority, the communication means with the highest priority is selected. .
- the invention according to claim 9 is the network system according to any one of claims 1 to 8, wherein the transmission preparation packet selection unit of the core node is configured to transmit a transmission priority to a packet stored in the transmission buffer. And the packet having the highest transmission priority is selected as a transmission preparation packet, and the transmission priority is set so that a packet having a long time stored in the transmission buffer is high, or Packets having different transmission priorities are set so that the next transmission node, which is the next node to be relayed, is matched when packets are transmitted by relay transmission, or packets having different transmission priorities The next transmission nodes are set so as not to coincide with each other.
- the invention according to claim 10 is the network system according to any one of claims 1 to 9, wherein the plurality of communication means perform transmission / reception of packets with other nodes by wireless communication, Different wireless channels are assigned to the communication means, and the wireless channels assigned to the communication means having the same uplink priority or downlink priority are the same on the network.
- the invention according to claim 11 is the network system according to any one of claims 1 to 9, wherein the plurality of communication means perform transmission / reception of packets with other nodes by wireless communication, Different radio channels are assigned to the communication means based on the interference reception level.
- the invention according to claim 12 is a node that transmits a transmission preparation packet to another node on the network, and is a plurality of communication means in which a downlink priority and an uplink priority are set as two types of priorities. And communication control means for selecting one communication means from the plurality of communication means according to the downlink priority or the uplink priority, and causing the selected communication means to transmit the transmission preparation packet.
- the node is a slave node
- the means selects one communication means according to the downlink priority and transmits the transmission preparation packet when the transmission source of the transmission preparation packet is a core node, and transmits the transmission preparation packet.
- the transmission destination of the packet When the transmission destination of the packet is the core node, select one communication means according to the uplink priority and transmit the transmission preparation packet, If the node is a core node, one communication unit is selected from the plurality of communication units in accordance with the downlink priority, and the transmission preparation packet is transmitted through the transmission standby state.
- the time from the time when the packet is transmitted to the time when the transmission preparation packet is transmitted is a predetermined time.
- the invention according to claim 13 is a packet forwarding method in a network including one core node and a plurality of slave nodes, wherein the core node and each slave node are a plurality of communication means for communicating with other nodes. Selecting one of the plurality of communication means according to one of the two types of priorities set to the plurality of communication means, that is, the uplink priority and the downlink priority, and transmitting a packet to the selected communication means Communication control means, and when the packet is relayed and transferred from the core node to the slave node, the communication control means of the core node selects one of the plurality of communication means according to the downlink priority, and selects the selected communication means.
- the packet In response to the relay transfer destination slave node, the packet is transmitted through a transmission standby state, and the packet
- the communication control means of the received slave node selects one of the plurality of communication means according to the downlink priority when the transmission destination of the packet is another slave node, and relays to the selected communication means
- the communication control unit of the slave node selects one of the plurality of communication units according to the uplink priority. The packet is transmitted to the selected communication means.
- the invention according to claim 14 is a program for causing a computer to function as the communication control means according to claim 12.
- the invention according to claim 15 is a recording medium for recording the program according to claim 14.
- the core node may include event generation means for generating an event when the transmission buffer is not empty, and the communication control means of the core node may select one communication means when an event is generated by the event generation means.
- the uplink priority and the downlink priority are opposite to each other so that the downlink priority is low when the uplink priority is high and the downlink priority is high when the uplink priority is low. It may be set so as to be.
- each of the nodes may operate as an access point, in which a plurality of terminals are connected under the node, and an uplink packet transmitted from the plurality of terminals or a downlink packet destined for the terminal is relayed and transmitted. Good.
- uplink or downlink happens to be free, transmission of the packet on the opposite line may be permitted (aggregation transmission of the uplink / downlink packet).
- communication quality can be further improved.
- periodic intermittent transmission is performed when uplink packets are transmitted on the downlink channel, and downlink interlocking periodic intermittent transmission is performed in the same manner as uplink packets when downlink packets are transmitted on the uplink channel. You may do it.
- each node is equipped with communication means such as a plurality of wireless interfaces, it is possible to realize IPT without requiring route reservation and achieve high relay transmission efficiency. It becomes.
- the effect of the periodic intermittent transmission is exhibited also in the uplink. (Downlink-linked periodic intermittent transmission).
- the packet stored in the transmission buffer is preferentially selected (FIFO transmission), or the next transmission is performed between packets having different transmission priorities.
- the nodes may be set to match (concentrated transmission), or the next transmission node may not be set to match between packets having different transmission priorities (round robin transmission).
- each relay node distributed in the space has a different degree of radio wave interference depending on the place where it is installed. Therefore, as in the invention according to claim 11, different channels may be assigned according to a communication state such as radio wave interference.
- the communication means of one node transmits a packet using the communication means. Otherwise, it may be adapted to the channel assigned to the communication means of the other node. In this way, by dynamically selecting a channel for each relay link and each packet, each relay node can always adaptively select the channel with the highest quality and improve the communication quality.
- the present invention can be widely applied to, for example, wireless communication systems in general, that is, relay transmission of wireless mesh points, fixed microwave radio, wireless LAN, land mobile communication, digital broadcasting, and the like.
- FIG. 1A shows a mesh cluster 1 which is an example of the mesh clusters 103, 105 and 107 in FIG. 1
- FIG. 1B shows an example of a tree-structured relay route rooted at the core node 3 included in the mesh cluster 1.
- FIG. It is a block diagram which shows an example of the core node 21 and slave node 41 which concern on embodiment of this invention. It is a flowchart which shows an example of operation
- FIG. 1 is a diagram illustrating an example of a wireless mesh network.
- the wireless mesh network 101 includes mesh clusters 103, 105, and 107.
- Each mesh cluster includes a plurality of nodes.
- a node is an element that constitutes a network.
- a node that operates as a computer or an access point (a plurality of terminals are connected to each node, and packets sent from these terminals at each node or Relaying packets destined for these terminals).
- the plurality of nodes can communicate with each other and are connected in a so-called mesh shape (see FIG. 2A).
- Each mesh cluster 103, 105, and 107 includes core nodes 111, 113, and 115, respectively.
- the core nodes 111, 113, and 115 are origin nodes connected to the wireline core network 109 that is an external network.
- nodes other than the core node are referred to as slave nodes.
- FIG. 2 is a diagram illustrating an example of a tree-structured relay route that has the mesh cluster 1 as an example of the mesh clusters 103, 105, and 107 in FIG. 1 and the core node 3 included in the mesh cluster 1 as a root.
- the mesh cluster 1 includes 9 nodes.
- One is a core node 3, and eight are slave nodes 5, 7, 9, 11, 13, 15, 17, 19.
- the core node 3 can directly communicate with the slave nodes 5, 7, and 9, the slave node 5 is the core node 3 and the slave node 11, the slave node 7 is the core node 3 and the slave nodes 11, 13, and 17, and the slave node 9 is The core node 3 and the slave nodes 17 and 19, the slave node 11 is the slave nodes 5, 7, and 13, the slave node 13 is the slave nodes 7, 11, and 15, the slave node 15 is the slave nodes 13 and 17, and the slave node 17 Assume that the slave nodes 7, 9, 15 and 19 can communicate directly with the slave nodes 19 and 17.
- a tree-structured relay path is set with the core node 3 as a root and branches between directly communicable nodes.
- Core node 3 has slave nodes 5, 7, and 9 as children
- slave node 5 has slave node 11 as a child
- slave node 7 has slave nodes 13 and 17 as children
- slave node 13 has slave node 15 as a child
- slave The node 9 has the slave node 19 as a child.
- the direction from the core node 3 toward each slave node is referred to as a downward direction
- the direction from each slave node toward the core node 3 is referred to as an upward direction.
- a packet transmitted from the core node 3 to the slave node is referred to as a downstream packet, and a packet transmitted from the slave node to the core node 3 is referred to as an upstream packet.
- a node to be relayed next when relaying a packet (for example, the slave node 7 when relaying from the core node 3 to the slave node 15) is referred to as a next transmission node.
- FIG. 3 is a block diagram showing an example of the core node 21 and the slave node 41 according to the embodiment of the present invention.
- FIG. 4 is a flowchart showing operations of the core node 21 and the slave node 41 of FIG.
- the configuration and operation of the core node and the slave node will be described with reference to FIGS. 3 and 4.
- the core node 21 includes a transmission buffer 23 that stores a packet to be transmitted, a reception buffer 25 that stores a received packet, and a buffer control unit 27 that controls the transmission buffer 23 and the reception buffer 25.
- a plurality of communication units 29 1 ,... 29 N that communicate with the slave node, a transmission preparation packet selection unit 31 that selects one packet from the packets stored in the transmission buffer 23 as a transmission preparation packet, and a packet Select one of the event generating unit 33 and the communication units 29 1 ,..., 29 N that generate a transmittable interrupt event when the transmission reference is true, and transmit a transmission preparation packet to the selected communication unit
- the communication control unit 35 is provided.
- the communication units 29 1 ,..., 29 N are wireless devices that are assigned different channels and communicate with the slave nodes wirelessly. Two types of priority, that is, uplink priority and downlink priority, are set in the communication units 29 1 ,..., 29 N.
- the communication units 29 1 ,..., 29 N are arranged in this order so that those having a high downlink priority have a low uplink priority and those having a high uplink priority have a low downlink priority. It is assumed that the downlink priority is set to be opposite.
- the communication unit 29 1 and most downlink priority is lower highest uplink priority is high
- the communication unit 29 2 next uplink priority is higher downlink priority is low
- the communication unit 29 N most upstream It is assumed that the priority is low and the downlink priority is the highest.
- the buffer control unit 27 stores the packets received by the communication units 29 1 ,..., 29 N in the reception buffer 25. Further, the buffer control unit 27 responds to the transmission buffer 23 with respect to, for example, a packet addressed to the slave node generated in the core node 21 or a slave node received from an external network (see the wireline core network 109 in FIG. 1). Stores the packet to be transmitted. Note that the packet stored in the transmission buffer 23 is a downstream packet and is transmitted from the core node to the slave node.
- the transmission preparation packet selection unit 31 sets a transmission priority for the packet group stored in the transmission buffer 23, and selects a packet with the highest transmission priority as a transmission preparation packet to be transmitted next.
- a packet stored in the transmission buffer 23 may have a high priority (FIFO transmission) so that the next transmission node does not match between packets having different transmission priorities. May be set (round robin transmission), or may be set so that the next transmission node matches between packets having different transmission orders (concentrated transmission).
- the event generation unit 33 generates a transmittable interrupt event when the packet transmission standard is true.
- a packet transmission standard for example, the transmission buffer 23 is not empty, and packets are actively transmitted to the slave node.
- the communication control unit 35 selects one communication unit according to the downlink priority, and sends a transmission preparation packet to the selected communication unit through a transmission standby state. Send it.
- FIG. 4A is a flowchart showing the operation of the communication control unit 35 in FIG.
- the communication control unit 35 first determines whether or not a transmittable interrupt event has occurred (step STC1).
- the communication control unit 35 selects a communication unit based on the downlink priority (step STC2). Specifically, when the number of packets stored in the transmission buffer 23 does not exceed a predetermined number PNT , the communication unit 29N having the highest downlink priority is selected. When the number of packets stored in the transmission buffer 23 exceeds PNT , for example, communication units 29 N , 29 N ⁇ 1 ,..., 29 1 , 29 N , 29 N ⁇ 1 ,. as such, selecting the next higher downlink priority communication section of the communication unit previously selected when the communication unit that was selected directly before is not the lowest priority communication unit 29 1, the communication unit is a communication that previously selected when the parts 29 1 to select the most downstream high priority communication section 29 N. As described above, the communication control unit 35 selects the communication unit according to the packet selection criterion corresponding to the state of the transmission buffer 23 according to the downlink priority.
- the communication control unit 35 for the selected communication unit, the time from the time when the packet was transmitted immediately before on the communication unit to the time when the transmission preparation packet is transmitted is, for example, the transmission preparation packet
- a transmission standby state is set so that the transmission period is set according to the packet length of the slave node or transmission preparation packet as the transmission destination (step STC3), and then transmitted to the selected communication unit.
- a preparation packet is transmitted (step STC4). Then, the process returns to step STC1.
- the slave node 41 transmits a transmission buffer 43 that stores a packet to be transmitted, a reception buffer 45 that stores a received packet, and a transmission Buffer control unit 47 that controls the buffer 43 and the reception buffer 45, a plurality of communication units 49 1 ,... 49 N that communicate with the slave nodes, and one packet prepared for transmission from the packets stored in the transmission buffer 43 Select one of transmission preparation packet selection unit 51 to be selected as a packet, event generation unit 53 that generates a transmittable interrupt event when the packet transmission reference is true, and communication units 49 1 ,..., 49 N
- the communication control unit 55 is configured to cause the selected communication unit to transmit a transmission preparation packet.
- the communication units 49 1 ,..., 49 N are wireless devices that are assigned different channels and communicate with other nodes wirelessly.
- the buffer control unit 47 stores the packets received by the communication units 49 1 ,..., 49 N in the reception buffer 45. Further, the buffer control unit 47 causes the transmission buffer 43 to store, for example, packets addressed to other nodes generated in the slave node 41 and packets addressed to other slave nodes received from other slave nodes.
- the packets stored in the transmission buffer 43 include upstream packets and downstream packets.
- the transmission preparation packet selection unit 51 sets a transmission priority for the packet group stored in the transmission buffer 43, and selects a packet with the highest transmission priority as a transmission preparation packet.
- a transmission priority for example, a packet stored for a long time in the transmission buffer 43 sets a high priority (FIFO transmission).
- the event generation unit 53 generates a transmittable interrupt event when the packet transmission standard is true.
- a new packet may be added to the transmission buffer 43 (downlink asynchronous IPT). Specifically, it is a case where a packet is received from another slave node or a core node, or a case where a packet is generated inside the slave node.
- a new downlink packet may be added to the transmission buffer 43 (downlink synchronization IPT).
- downlink synchronization IPT downlink synchronization
- more efficient relay transmission can be achieved by using downlink synchronization. That is, downlink synchronization focuses on the fact that the downlink is relayed as if the core node is polling.
- a downlink packet relayed and transmitted by IPT in the downlink is regarded as a polling signal and transmitted in synchronization therewith. By this transmission, relay packet collision is avoided, and more efficient relay transmission efficiency can be achieved.
- downlink synchronization when there is not much downlink packet reception, there is a possibility that uplink packets will accumulate in the slave node.
- an empty downlink packet may be periodically transmitted from the core node by IPT, and the event generating unit 53 does not wait for reception of a packet from another node, and the slave node does not wait for reception of the packet. If more than a few packets accumulate, a transmittable interrupt event may be generated and packet transmission of the transmission buffer 43 may be performed.
- the communication control unit 55 follows the uplink priority when the transmission preparation packet is an uplink packet, and follows the downlink priority when the transmission preparation packet is a downlink packet. One communication unit is selected, and a transmission preparation packet is transmitted to the selected communication unit.
- FIG. 4B is a flowchart showing the operation of the communication control unit 55 in FIG.
- the communication control unit 55 first determines whether or not a transmittable interrupt event has occurred (step STS1).
- the communication control unit 35 determines whether or not the transmission preparation packet is an uplink packet (step STS2).
- the communication control unit 35 selects a communication unit according to the uplink priority in the same manner as described in step STC2 of FIG. 4 (step STS3).
- the communication control unit 35 selects a communication unit according to the downlink priority in the same manner as described in step STC2 of FIG. 4 (step STS4).
- the communication control unit 35 causes the selected communication unit to transmit a transmission preparation packet without going through a communication standby state (step STS5). Then, the process returns to step STS1.
- the operations of the core node and slave node can be summarized as shown in the following table. That is, only the slave node is related to the transmission of the uplink packet, but the selection of the communication unit is performed according to the uplink priority, and the transmission process is performed by the occurrence of the transmittable interrupt event. On the other hand, transmission of the downlink packet is performed by both the core node and the slave node. The communication unit is selected according to the downlink priority. The core node periodically transmits packets, and the slave node performs transmission processing upon occurrence of a transmittable interrupt event.
- the communication units having the same uplink priority or downlink priority may allocate the same radio channel in all nodes (fixed channel allocation).
- each communication unit is assigned a radio channel that is least susceptible to radio wave interference at the relay destination node that is the relay destination of the slave node, and is assigned to a radio device having the same uplink priority or downlink priority.
- the relay destination node may be adapted to the radio channel of the relay source node except when the node transmits (dynamic channel selection).
- interference can be further reduced by dynamic channel selection. That is, assuming application of the ISM band, there are two sources of interference: interference generated from a neighboring trunk line generated in its own mesh cluster and interference generated from another wireless system. Channels that are least susceptible to interference are dynamically selected for each relay link, and robust relay transmission can be realized even under the ISM band. By performing dynamic channel selection based on IPT, a synergistic effect with multi-channel IPT can be exhibited.
- the traffic that flows is sparse at nodes located outside the mesh cluster. For example, in a situation where only the downlink is transmitted, the lane reserved for the uplink is hardly used. Therefore, between the slave nodes, packets in the opposite direction may be sent to the unused lane (link borrowing).
- FIG. 5 is a diagram showing the arrangement of nodes in the simulation of the present invention.
- the simulation specifications will be explained.
- the wireless IF is IEEE 802.11a (54 Mbps).
- the data packet size is 1500 bytes and the simulation time is 180 seconds.
- the traffic model is only UDP traffic, the call is generated by Poisson at the base station, the number of packets per packet burst follows a lognormal distribution (Uplink has an average of 3 packets, Downlink has an average of 20 packets, and the upper and lower total traffic ratio is 1:10.). IPT applies only to downlink traffic from the core node.
- FIG. 6 is a diagram showing a comparison between the system throughput and the prior art in which IPT is applied only to the downlink channel according to the embodiment of the present invention (hereinafter referred to as “DL-IPT”).
- the three prior arts to be compared are those in which only one channel (IF) is used (SingleCh; hereinafter referred to as “prior art 1”), and two radio IFs are used for uplink and downlink.
- IF only one channel
- prior art 1 SingleCh
- Each channel is assigned a channel (DualCh; UL &DL; hereinafter referred to as “conventional technology 2”), and each channel is used without distinction between uplink and downlink (DualCh; Mixed; hereinafter referred to as “conventional technology 3”). It is.
- the horizontal axis is the call volume
- the vertical axis is the total throughput.
- the throughput is about 12 Mbps at the highest in the conventional technique 1 and about 13 Mbps at the highest in the conventional technique 2.
- it is at most about 24 Mbps, which is about twice that of the prior art 1 and the prior art 2.
- the DL-IPT which is an embodiment of the present invention, about 27 Mbps is achieved, which is an improvement of about 12% compared with the prior art 3.
- the system throughput is greatly improved by passing the downlink traffic on the uplink.
- FIG. 7 is a diagram showing a comparison between DL-IPT, which is an embodiment of the present invention, and the prior art with respect to the average delay per packet.
- the average delay is the time from when a packet is stored in the queue until it reaches the final destination node.
- the horizontal axis is the call volume
- the vertical axis is the average delay. Comparing the value of call volume when the average delay exceeds 0.5 [sec / Packet], it is about 12 Mbps in the conventional technique 1, about 13 Mbps in the conventional technique 2, and about 24 Mbps in the conventional technique 3.
- the DL-IPT which is an embodiment of the present invention, it is about 26 Mbps, which is a significant improvement over the prior art.
- FIG. 8 is a diagram showing a comparison between the DL-IPT, which is an embodiment of the present invention, and the prior art regarding the packet loss rate in downlink traffic.
- the packet loss rate is obtained by dividing the number of buckets discarded beyond the maximum number of retransmissions by the sum of the number of packets successfully received and the number of discarded packets.
- the horizontal axis represents the call volume
- the vertical axis represents the packet loss rate.
- it is 0.02% or more at the lowest, and increases to about 0.05% when the call volume exceeds 20 Mbps.
- the DL-IPT which is an embodiment of the present invention, it is almost equal to 0, which is 0.01 or less, which is a significant improvement compared to the prior art 3.
- FIG. 9 is a diagram showing a comparison between the DL-IPT, which is an embodiment of the present invention, and the prior art with respect to the packet loss rate in uplink traffic.
- the horizontal axis represents the call volume
- the vertical axis represents the packet loss rate.
- the conventional technique 3 is 0.05% or less at most
- the DL-IPT according to the embodiment of the present invention has the same value as the conventional technique 3 when the call volume is low. However, it increases to around 0.08% as the call volume increases.
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Abstract
Disclosed are a network system and so forth for realizing packet relay transmission with higher efficiency in relay transmission in the intermittent periodic transmit (IPT) method. A communication control section (35) of a core node (21) selects one of a plurality of communication sections (291, ,29N) according to down priority to Intermittent-Periodically transmit a packet in order to realize the Intermittent Periodic Transmit in a mesh cluster. A communication control section (55) of a slave node (41) selects one communication section according to the down priority when transmitting the packet from the core node to another slave node and selects one communication section according to up priority to transmit the packet to the selected communication section when transmitting the packet from the slave node to the core node.
Description
本願発明は、ネットワークシステム、ノード、パケット送信方法、プログラム及び記録媒体に関し、特に1つのコアノードと複数のスレーブノードを含むネットワークシステム等に関する。
The present invention relates to a network system, a node, a packet transmission method, a program, and a recording medium, and more particularly to a network system including one core node and a plurality of slave nodes.
低コストモバイル通信インフラのバックホールネットワークとして、無線メッシュネットワークが注目されている。無線メッシュネットワークは、基地局間を専用の無線で中継接続し、有線バックホール回線の敷設を不要にし、モバイル通信システム導入に要する敷設コストを大幅に削減可能な技術である。将来のブロードバンド通信ではセルの狭小化は避けられず、極めて多数の基地局を設置しなければならなくなり、基地局敷設コストの増大が深刻な問題となる。無線メッシュネットワークはこの問題を解決する唯一の技術である。
Wireless mesh networks are attracting attention as a backhaul network for low-cost mobile communication infrastructure. The wireless mesh network is a technology that can significantly reduce the installation cost required for introducing a mobile communication system by connecting base stations with a dedicated wireless relay, eliminating the need for a wired backhaul line. In future broadband communications, the narrowing of cells is inevitable, and an extremely large number of base stations must be installed, which increases the cost of laying base stations. Wireless mesh networks are the only technology that solves this problem.
発明者らは、複数のノードが配置されたマルチホップネットワークにおいて伝送効率の高いパケット中継伝送を実現する周期的間欠送信法(Intermittent Periodic Transmit。以下、「IPT」という。)を提案している(特許文献1、特許文献2、特許文献3参照)。
The inventors have proposed a periodic intermittent transmission method (hereinafter referred to as “IPT”) that realizes packet relay transmission with high transmission efficiency in a multi-hop network in which a plurality of nodes are arranged. (See Patent Literature 1, Patent Literature 2, and Patent Literature 3).
IPTでは、プロトコルが、上下回線を一車線通路上で伝送することを前提として設計されていた。そのため、上下回線が混在したり、車線が枝分かれしたりした場合に、大きな特性劣化を生じていた。
In IPT, the protocol was designed on the assumption that the upper and lower lines are transmitted in a single lane path. Therefore, when the upper and lower lines are mixed or the lanes are branched, the characteristics are greatly deteriorated.
IPTは、原理的に、1次元配列された中継リンクのもとで最大の効果を発揮するが、現実は2次元あるいは3次元的に中継ノードは分散配置される。そこで、発明者らは、特許文献3にあるように、経路予約を適用することによっていかなるネットワークトポロジーの下でも周期的間欠送信の効果を発揮することが可能な手法を考案した。しかしながら、経路予約法によっては、経路予約のためのオーバヘッドが生じてしまう。
IPT, in principle, exhibits the maximum effect under a one-dimensionally arranged relay link, but in reality, relay nodes are distributed in two or three dimensions. Therefore, the inventors have devised a technique capable of exerting the effect of periodic intermittent transmission under any network topology by applying route reservation as disclosed in Patent Document 3. However, depending on the route reservation method, overhead for route reservation occurs.
そこで、本願発明は、IPTにおいて、より中継伝送効率の高いパケット中継伝送を実現するネットワークシステム、ノード、パケットフォワーディング方法、プログラム及び記録媒体を提案することを目的とする。
Therefore, an object of the present invention is to propose a network system, a node, a packet forwarding method, a program, and a recording medium that realize packet relay transmission with higher relay transmission efficiency in IPT.
請求項1に係る発明は、1つのコアノードと複数のスレーブノードを含むネットワークシステムにおいて、前記各スレーブノードは、前記コアノードから他のスレーブノードに対して送信されたパケットである下りパケット、及び、スレーブノードから前記コアノードに対して送信されたパケットである上りパケットを格納する送信バッファと、他のノードからパケットを受信し、及び、他のノードに対して前記送信バッファに格納されたパケットを送信し、並びに、2種類の優先度である下り優先度及び上り優先度が設定された複数の通信手段と、前記送信バッファに格納されたパケットから送信準備パケットを選択する送信準備パケット選択手段と、前記送信準備パケットが前記下りパケットであれば前記下り優先度に従って、又は、前記送信準備パケットが前記上りパケットであれば前記上り優先度に従って、1つの通信手段を選択し、選択された通信手段に対して前記送信準備パケットを送信させる通信制御手段を備え、前記コアノードは、パケットを格納する送信バッファと、スレーブノードからパケットを受信し、及び、スレーブノードに対して前記送信バッファに格納されたパケットを送信し、並びに、2種類の優先度である下り優先度及び上り優先度が設定された複数の通信手段と、前記送信バッファに格納されたパケットから送信準備パケットを選択する送信準備パケット選択手段と、前記下り優先度に従って1つの通信手段を選択し、選択された通信手段に対して、送信待機状態を経て前記送信準備パケットを送信させることにより、当該通信手段上で直前にパケットを送信し終えた時刻から前記送信準備パケットを送信させる時刻までの時間を所定の時間とする通信制御手段を備えるものである。
The invention according to claim 1 is a network system including one core node and a plurality of slave nodes, wherein each slave node is a downlink packet transmitted from the core node to another slave node, and a slave A transmission buffer that stores an upstream packet that is a packet transmitted from the node to the core node; a packet that is received from another node; and a packet that is stored in the transmission buffer is transmitted to another node. A plurality of communication means in which downlink priority and uplink priority which are two types of priority are set, transmission preparation packet selection means for selecting a transmission preparation packet from packets stored in the transmission buffer, and If the transmission preparation packet is the downlink packet, according to the downlink priority, or If the transmission preparation packet is the uplink packet, the communication preparation unit selects one communication unit according to the uplink priority, and causes the selected communication unit to transmit the transmission preparation packet. Transmission buffer for storing packets, receiving packets from slave nodes, transmitting packets stored in the transmission buffer to slave nodes, and two types of priority, downlink priority and uplink priority A plurality of communication means for which a degree is set, a transmission preparation packet selection means for selecting a transmission preparation packet from the packets stored in the transmission buffer, and one communication means according to the downlink priority, and the selected communication By causing the means to transmit the transmission preparation packet through a transmission standby state, the communication means immediately before the communication means The time of a packet from the time it has finished sending a until the time to transmit the transmission ready packet in which a communication control means for a predetermined time.
請求項2に係る発明は、請求項1記載のネットワークシステムであって、前記各スレーブノードは、下りパケットを受信した場合にイベントを発生するイベント発生手段を備え、前記スレーブノードの前記通信制御手段は、前記スレーブノードの前記イベント発生手段によりイベントが発生した場合に1つの通信手段を選択するものである。
The invention according to claim 2 is the network system according to claim 1, wherein each of the slave nodes includes event generation means for generating an event when a downlink packet is received, and the communication control means of the slave node Is to select one communication means when an event is generated by the event generation means of the slave node.
請求項3に係る発明は、請求項2記載のネットワークシステムであって、前記コアノードは、スレーブノードに対して、定期的にパケットを送信するものである。
The invention according to claim 3 is the network system according to claim 2, wherein the core node periodically transmits a packet to a slave node.
請求項4に係る発明は、請求項2又は3記載のネットワークシステムであって、前記イベント発生手段は、前記送信バッファに所定の数以上のパケットが格納されていた場合にイベントを発生するものである。
The invention according to claim 4 is the network system according to claim 2 or 3, wherein the event generation means generates an event when a predetermined number or more packets are stored in the transmission buffer. is there.
請求項5に係る発明は、請求項1記載のネットワークシステムであって、前記各スレーブノードは、前記送信バッファに新たなパケットが追加された場合にイベントを発生するイベント発生手段を備え、前記スレーブノードの前記通信制御手段は、前記スレーブノードの前記イベント発生手段によりイベントが発生した場合に1つの通信手段を選択するものである。
The invention according to claim 5 is the network system according to claim 1, wherein each of the slave nodes includes event generation means for generating an event when a new packet is added to the transmission buffer. The communication control means of a node selects one communication means when an event occurs by the event generation means of the slave node.
請求項6に係る発明は、請求項1から5のいずれかに記載のネットワークシステムであって、前記上り優先度の最も高い通信手段と前記下り優先度の最も高い通信手段とが異なるものである。
The invention according to claim 6 is the network system according to any one of claims 1 to 5, wherein the communication means having the highest uplink priority and the communication means having the highest downlink priority are different. .
請求項7に係る発明は、請求項1から6のいずれかに記載のネットワークシステムであって、前記コアノードの前記通信制御手段が、当該通信手段上で直前にパケットを送信し終えた時刻から前記送信準備パケットを送信させる時刻までの時間を、前記送信準備パケットの送信先となるスレーブノード及び前記送信準備パケットのパケット長の少なくとも一方に応じて設定される送信周期とするものである。
The invention according to claim 7 is the network system according to any one of claims 1 to 6, wherein the communication control unit of the core node has transmitted the packet immediately before on the communication unit. The time until the time when the transmission preparation packet is transmitted is a transmission cycle set according to at least one of the slave node that is the transmission destination of the transmission preparation packet and the packet length of the transmission preparation packet.
請求項8に係る発明は、請求項1から7のいずれかに記載のネットワークシステムであって、前記コアノード及び前記スレーブノードの少なくとも一方の前記通信制御手段は、前記送信バッファに格納されたパケットの数が所定の数PNTを超えない場合、最も優先度の高い通信手段を選択し、送信バッファに格納されたパケットの数がPNTを超える場合、直前に選択した通信手段が最も優先度の低い通信手段ではないときは次に優先順位の高い通信手段を選択し、直前に選択した通信手段が最も優先度の低い通信手段であるときは最も優先度の高い通信手段を選択するものである。
The invention according to claim 8 is the network system according to any one of claims 1 to 7, wherein the communication control means of at least one of the core node and the slave node is configured to transmit packets stored in the transmission buffer. If the number does not exceed the predetermined number P NT, the highest-priority communication section is selected, if the number of stored in the transmission buffer packet exceeds P NT, the communication means selected immediately before the highest priority When not a low communication means, the communication means with the next highest priority is selected, and when the communication means selected immediately before is the communication means with the lowest priority, the communication means with the highest priority is selected. .
請求項9に係る発明は、請求項1から8のいずれかに記載のネットワークシステムであって、前記コアノードの前記送信準備パケット選択手段は、前記送信バッファに格納されたパケットに対して送信優先順位を設定し、送信優先順位の最も高いパケットを送信準備パケットとして選択するものであり、前記送信優先順位は、前記送信バッファに格納された時間が長いパケットが高くなるように設定されるか、前記送信優先順位が一つ異なるパケット間で、パケットを中継伝送する場合に次に中継すべきノードである次伝送ノードが一致するように設定されるか、又は、前記送信優先順位が一つ異なるパケット間で次伝送ノードが一致しないように設定されるものである。
The invention according to claim 9 is the network system according to any one of claims 1 to 8, wherein the transmission preparation packet selection unit of the core node is configured to transmit a transmission priority to a packet stored in the transmission buffer. And the packet having the highest transmission priority is selected as a transmission preparation packet, and the transmission priority is set so that a packet having a long time stored in the transmission buffer is high, or Packets having different transmission priorities are set so that the next transmission node, which is the next node to be relayed, is matched when packets are transmitted by relay transmission, or packets having different transmission priorities The next transmission nodes are set so as not to coincide with each other.
請求項10に係る発明は、請求項1から9のいずれかに記載のネットワークシステムであって、前記複数の通信手段は無線通信により他のノードとパケットの送受信を行うものであり、前記複数の通信手段には、それぞれ異なる無線チャネルが割り当てられ、前記ネットワーク上において、上り優先度又は下り優先度が同一の通信手段に割り当てられる前記無線チャネルは同一である。
The invention according to claim 10 is the network system according to any one of claims 1 to 9, wherein the plurality of communication means perform transmission / reception of packets with other nodes by wireless communication, Different wireless channels are assigned to the communication means, and the wireless channels assigned to the communication means having the same uplink priority or downlink priority are the same on the network.
請求項11に係る発明は、請求項1から9のいずれかに記載のネットワークシステムであって、前記複数の通信手段は無線通信により他のノードとパケットの送受信を行うものであり、前記複数の通信手段には、それぞれ、干渉受信レベルに基づいて異なる無線チャネルが割り当てられるものである。
The invention according to claim 11 is the network system according to any one of claims 1 to 9, wherein the plurality of communication means perform transmission / reception of packets with other nodes by wireless communication, Different radio channels are assigned to the communication means based on the interference reception level.
請求項12に係る発明は、ネットワーク上の他のノードに対して送信準備パケットを送信するノードであって、2種類の優先度である下り優先度及び上り優先度が設定された複数の通信手段と、前記下り優先度又は前記上り優先度に従って前記複数の通信手段から1つの通信手段を選択し、選択された通信手段に対して前記送信準備パケットを送信させる通信制御手段を備え、前記通信制御手段は、当該ノードがスレーブノードの場合には、前記送信準備パケットの送信元がコアノードであるときは前記下り優先度に従って1つの通信手段を選択して前記送信準備パケットを送信させ、前記送信準備パケットの送信先が前記コアノードであるときは前記上り優先度に従って1つの通信手段を選択して前記送信準備パケットを送信させ、当該ノードがコアノードの場合には、前記下り優先度に従って前記複数の通信手段から1つの通信手段を選択し、送信待機状態を経て前記送信準備パケットを送信させることにより、当該通信手段上で直前にパケットを送信し終えた時刻から前記送信準備パケットを送信させる時刻までの時間を所定の時間とするものである。
The invention according to claim 12 is a node that transmits a transmission preparation packet to another node on the network, and is a plurality of communication means in which a downlink priority and an uplink priority are set as two types of priorities. And communication control means for selecting one communication means from the plurality of communication means according to the downlink priority or the uplink priority, and causing the selected communication means to transmit the transmission preparation packet. When the node is a slave node, the means selects one communication means according to the downlink priority and transmits the transmission preparation packet when the transmission source of the transmission preparation packet is a core node, and transmits the transmission preparation packet. When the transmission destination of the packet is the core node, select one communication means according to the uplink priority and transmit the transmission preparation packet, If the node is a core node, one communication unit is selected from the plurality of communication units in accordance with the downlink priority, and the transmission preparation packet is transmitted through the transmission standby state. The time from the time when the packet is transmitted to the time when the transmission preparation packet is transmitted is a predetermined time.
請求項13に係る発明は、1つのコアノードと複数のスレーブノードを含むネットワークにおけるパケットフォワーディング方法であって、前記コアノード及び前記各スレーブノードは、他のノードと通信をするための複数の通信手段と、前記複数の通信手段に設定された2種類の優先度である上り優先度及び下り優先度のいずれかに従って前記複数の通信手段の1つを選択し、選択した通信手段に対してパケットを送信させる通信制御手段を備え、前記コアノードから前記スレーブノードにパケットを中継転送する場合、前記コアノードの通信制御手段が、下り優先度に従って前記複数の通信手段のいずれかを選択し、選択した通信手段に対して中継転送先のスレーブノードに送信待機状態を経て当該パケットを送信させ、前記パケットを受信したスレーブノードの通信制御手段は、当該パケットの送信先が他のスレーブノードである場合には、下り優先度に従って前記複数の通信手段の1つを選択し、選択した通信手段に対して中継転送先のスレーブノードに当該パケットを送信させ、前記スレーブノードから前記コアノードにパケットを中継転送する場合、前記スレーブノードの通信制御手段が、上り優先度に従って前記複数の通信手段の1つを選択し、選択した通信手段に対して当該パケットを送信させるものである。
The invention according to claim 13 is a packet forwarding method in a network including one core node and a plurality of slave nodes, wherein the core node and each slave node are a plurality of communication means for communicating with other nodes. Selecting one of the plurality of communication means according to one of the two types of priorities set to the plurality of communication means, that is, the uplink priority and the downlink priority, and transmitting a packet to the selected communication means Communication control means, and when the packet is relayed and transferred from the core node to the slave node, the communication control means of the core node selects one of the plurality of communication means according to the downlink priority, and selects the selected communication means. In response to the relay transfer destination slave node, the packet is transmitted through a transmission standby state, and the packet The communication control means of the received slave node selects one of the plurality of communication means according to the downlink priority when the transmission destination of the packet is another slave node, and relays to the selected communication means When transmitting the packet to the slave node of the transfer destination and relaying the packet from the slave node to the core node, the communication control unit of the slave node selects one of the plurality of communication units according to the uplink priority. The packet is transmitted to the selected communication means.
請求項14に係る発明は、コンピュータを、請求項12記載の通信制御手段として機能させるためのプログラムである。
The invention according to claim 14 is a program for causing a computer to function as the communication control means according to claim 12.
請求項15に係る発明は、請求項14記載のプログラムを記録する記録媒体である。
The invention according to claim 15 is a recording medium for recording the program according to claim 14.
なお、コアノードは、送信バッファが空でない場合にイベントを発生するイベント発生手段を備え、コアノードの通信制御手段は、イベント発生手段によりイベントが発生した場合に1つの通信手段を選択してもよい。
Note that the core node may include event generation means for generating an event when the transmission buffer is not empty, and the communication control means of the core node may select one communication means when an event is generated by the event generation means.
また、請求項6に係る発明において、上り優先度と下り優先度は、上り優先度が高いものは下り優先度が低く、上り優先度が低いものは下り優先度が高くなるように、正反対となるように設定されるものであってもよい。
Further, in the invention according to claim 6, the uplink priority and the downlink priority are opposite to each other so that the downlink priority is low when the uplink priority is high and the downlink priority is high when the uplink priority is low. It may be set so as to be.
さらに、ノードは、それぞれ、その配下に複数の端末が接続され、前記複数の端末から発せられた上りパケット又は前記端末に向けた下りパケットを中継伝送する、アクセスポイントとして動作するものであってもよい。
Further, each of the nodes may operate as an access point, in which a plurality of terminals are connected under the node, and an uplink packet transmitted from the plurality of terminals or a downlink packet destined for the terminal is relayed and transmitted. Good.
さらに、上り回線又は下り回線がたまたま空いている場合には反対回線のパケットの伝送を許可するようにしてもよい(上下回線パケットのアグリゲーション伝送)。これにより、通信品質をさらに改善することができる。また、例えば、下り回線チャネル上で上りパケットを伝送する際は周期的間欠送信を、上り回線チャネル上で下りパケットを伝送する際は、下り連動型周期的間欠送信を上りパケットと同様に実施するようにしてもよい。
Furthermore, if the uplink or downlink happens to be free, transmission of the packet on the opposite line may be permitted (aggregation transmission of the uplink / downlink packet). Thereby, communication quality can be further improved. Also, for example, periodic intermittent transmission is performed when uplink packets are transmitted on the downlink channel, and downlink interlocking periodic intermittent transmission is performed in the same manner as uplink packets when downlink packets are transmitted on the uplink channel. You may do it.
本願発明によれば、各ノードに、例えば複数の無線インターフェースなどの通信手段を装備したマルチチャネル環境のもとで、経路予約の必要なくIPTを実現し、高い中継伝送効率を達成することが可能となる。
According to the present invention, in a multi-channel environment in which each node is equipped with communication means such as a plurality of wireless interfaces, it is possible to realize IPT without requiring route reservation and achieve high relay transmission efficiency. It becomes.
すなわち、コアノード(有線回線に接続された起点ノード)に対する上りトラフィックとコアノードからの下りトラフィックを異なる無線IFで分けて扱うことにより、両回線種間の干渉を排除する。さらに、下りトラフィックがコアノードを主導者とするポーリング型アクセスであることに着目し、従来のような予約手順を必要なくして経路選択を行い、周期的間欠送信を実現することができる。
That is, by treating the upstream traffic for the core node (starting node connected to the wired line) and the downstream traffic from the core node separately by different wireless IFs, interference between both types of lines is eliminated. Further, paying attention to the fact that the downlink traffic is a polling type access led by the core node, it is possible to perform periodic intermittent transmission by performing route selection without requiring a reservation procedure as in the prior art.
また、請求項2に係る発明にあるように、経路選択周期的間欠送信により伝送された下りパケットをあたかも上りのポーリング信号のように扱うことにより、上り回線においても周期的間欠送信の効果を発揮することができる(下り連動型周期的間欠送信)。
Further, as in the invention according to claim 2, by treating the downlink packet transmitted by the path selection periodic intermittent transmission as if it is an uplink polling signal, the effect of the periodic intermittent transmission is exhibited also in the uplink. (Downlink-linked periodic intermittent transmission).
さらに、請求項9に係る発明にあるように、前記送信バッファに格納された時間が長いパケットを優先的に選択するようにしたり(FIFO送信)、送信優先順位が一つ異なるパケット間で次伝送ノードが一致するように設定したり(集中送信)、前記送信優先順位が一つ異なるパケット間で次伝送ノードが一致しないように設定したり(ラウンドロビン送信)してもよく、この場合、例えばパケットバッファとスケジューリングにより同一方向のパケットをまとめて伝送することにより、異なる宛先のパケット間の干渉を抑制し、更なる中継伝送効率を達成することができる。
Furthermore, as in the invention according to claim 9, the packet stored in the transmission buffer is preferentially selected (FIFO transmission), or the next transmission is performed between packets having different transmission priorities. The nodes may be set to match (concentrated transmission), or the next transmission node may not be set to match between packets having different transmission priorities (round robin transmission). By collectively transmitting packets in the same direction by the packet buffer and scheduling, it is possible to suppress interference between packets of different destinations and achieve further relay transmission efficiency.
さらに、空間に分散配置された各中継ノードはそれぞれ設置された場所に応じて受ける電波干渉の程度も異なる。そのため、請求項11に係る発明にあるように、例えば電波干渉などの通信状態に応じて、異なるチャネルが割り当てられる場合があってもよい。この場合、通信がなされる2つのノード間で上り優先度又は下り優先度が等しい通信手段に割り当てられたチャネルが異なるときは、一方のノードの通信手段は、当該通信手段を用いてパケットを送信するとき以外は、他方のノードの通信手段に割り当てられたチャネルに合わせるようにしてもよい。このように、中継リンク毎、パケット毎に動的にチャネルを選択することにより、各中継ノードが常に一番品質の良いチャネルを適応的に選択し、通信品質の改善をすることができる。
Furthermore, each relay node distributed in the space has a different degree of radio wave interference depending on the place where it is installed. Therefore, as in the invention according to claim 11, different channels may be assigned according to a communication state such as radio wave interference. In this case, when the channels assigned to the communication means having the same uplink priority or downlink priority are different between the two nodes to be communicated, the communication means of one node transmits a packet using the communication means. Otherwise, it may be adapted to the channel assigned to the communication means of the other node. In this way, by dynamically selecting a channel for each relay link and each packet, each relay node can always adaptively select the channel with the highest quality and improve the communication quality.
本願発明は、例えば無線通信システム全般、すなわち、無線メッシュポイントの中継伝送、固定マイクロ波無線、無線LAN、陸上移動通信、ディジタル放送などにわたり広く適用可能である。
The present invention can be widely applied to, for example, wireless communication systems in general, that is, relay transmission of wireless mesh points, fixed microwave radio, wireless LAN, land mobile communication, digital broadcasting, and the like.
21 コアノード、23 送信バッファ、291,・・・,29N 通信部、31 送信準備パケット選択部、33 イベント発生部、35 通信制御部、41 スレーブノード、43 送信バッファ、491,・・・,49N 通信部、51 送信準備パケット選択部、53 イベント発生部、55 通信制御部、
21 core node, 23 transmission buffer, 29 1 ,..., 29 N communication unit, 31 transmission preparation packet selection unit, 33 event generation unit, 35 communication control unit, 41 slave node, 43 transmission buffer, 49 1 ,. 49 N communication unit, 51 transmission preparation packet selection unit, 53 event generation unit, 55 communication control unit,
以下では、図面を参照して、本願発明の実施の形態について説明する。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
図1は、無線メッシュネットワークの一例を示す図である。図1において、無線メッシュネットワーク101は、メッシュクラスタ103、105、107を含む。各メッシュクラスタは複数のノードを含む。ノードは、ネットワークを構成する一つ一つの要素であり、例えば、コンピュータ、アクセスポイントとして動作するもの(各ノードの配下に複数の端末が接続され、各ノードにおいてこれらの端末から発せられたパケットもしくはこれらの端末へ向けたパケットを中継伝送するもの)である。複数のノードは相互に通信可能であり、いわばメッシュ状に接続されたものである(図2(a)参照)。各メッシュクラスタ103、105、107には、それぞれ、コアノード111、113、115が含まれている。コアノード111、113、115は、外部ネットワークであるワイヤライン・コア・ネットワーク109と接続した起点ノードである。なお、以下では、メッシュクラスタにおいて、コアノード以外のノードをスレーブノードという。
FIG. 1 is a diagram illustrating an example of a wireless mesh network. In FIG. 1, the wireless mesh network 101 includes mesh clusters 103, 105, and 107. Each mesh cluster includes a plurality of nodes. A node is an element that constitutes a network. For example, a node that operates as a computer or an access point (a plurality of terminals are connected to each node, and packets sent from these terminals at each node or Relaying packets destined for these terminals). The plurality of nodes can communicate with each other and are connected in a so-called mesh shape (see FIG. 2A). Each mesh cluster 103, 105, and 107 includes core nodes 111, 113, and 115, respectively. The core nodes 111, 113, and 115 are origin nodes connected to the wireline core network 109 that is an external network. In the following, in the mesh cluster, nodes other than the core node are referred to as slave nodes.
図2は、図1のメッシュクラスタ103、105、107の一例であるメッシュクラスタ1と、メッシュクラスタ1に含まれるコアノード3を根とする木構造の中継経路の一例を示す図である。
FIG. 2 is a diagram illustrating an example of a tree-structured relay route that has the mesh cluster 1 as an example of the mesh clusters 103, 105, and 107 in FIG. 1 and the core node 3 included in the mesh cluster 1 as a root.
図2(a)に示されているように、メッシュクラスタ1には9個のノードが含まれている。1個はコアノード3であり、8個はスレーブノード5、7、9、11、13、15、17、19である。コアノード3はスレーブノード5、7、9と直接に通信可能であり、スレーブノード5はコアノード3及びスレーブノード11と、スレーブノード7はコアノード3及びスレーブノード11、13、17と、スレーブノード9はコアノード3及びスレーブノード17、19と、スレーブノード11はスレーブノード5、7、13と、スレーブノード13はスレーブノード7、11、15と、スレーブノード15はスレーブノード13、17と、スレーブノード17はスレーブノード7、9、15、19と、スレーブノード19はスレーブノード9、17と、直接通信可能であるとする。
As shown in FIG. 2A, the mesh cluster 1 includes 9 nodes. One is a core node 3, and eight are slave nodes 5, 7, 9, 11, 13, 15, 17, 19. The core node 3 can directly communicate with the slave nodes 5, 7, and 9, the slave node 5 is the core node 3 and the slave node 11, the slave node 7 is the core node 3 and the slave nodes 11, 13, and 17, and the slave node 9 is The core node 3 and the slave nodes 17 and 19, the slave node 11 is the slave nodes 5, 7, and 13, the slave node 13 is the slave nodes 7, 11, and 15, the slave node 15 is the slave nodes 13 and 17, and the slave node 17 Assume that the slave nodes 7, 9, 15 and 19 can communicate directly with the slave nodes 19 and 17.
図2(b)に示されているように、メッシュクラスタ1において、コアノード3を根とし、直接通信可能なノード間を枝とする木構造の中継経路を設定する。コアノード3はスレーブノード5、7、9を子とし、スレーブノード5はスレーブノード11を子とし、スレーブノード7はスレーブノード13、17を子とし、スレーブノード13はスレーブノード15を子とし、スレーブノード9はスレーブノード19を子とするとする。なお、以下では、コアノード3から各スレーブノードへ向かう方向を下り方向とし、各スレーブノードからコアノード3へ向かう方向を上り方向という。また、コアノード3からスレーブノードへ送信されたパケットを下りパケットといい、スレーブノードからコアノード3へ送信されたパケットを上りパケットという。また、パケットを中継伝送する場合に次に中継すべきノード(例えば、コアノード3からスレーブノード15へ中継伝送する場合のスレーブノード7)を次伝送ノードという。
As shown in FIG. 2 (b), in the mesh cluster 1, a tree-structured relay path is set with the core node 3 as a root and branches between directly communicable nodes. Core node 3 has slave nodes 5, 7, and 9 as children, slave node 5 has slave node 11 as a child, slave node 7 has slave nodes 13 and 17 as children, slave node 13 has slave node 15 as a child, slave The node 9 has the slave node 19 as a child. Hereinafter, the direction from the core node 3 toward each slave node is referred to as a downward direction, and the direction from each slave node toward the core node 3 is referred to as an upward direction. A packet transmitted from the core node 3 to the slave node is referred to as a downstream packet, and a packet transmitted from the slave node to the core node 3 is referred to as an upstream packet. A node to be relayed next when relaying a packet (for example, the slave node 7 when relaying from the core node 3 to the slave node 15) is referred to as a next transmission node.
図3は、本願発明の実施の形態に係るコアノード21及びスレーブノード41の一例を示すブロック図である。また、図4は、図3のコアノード21及びスレーブノード41の動作を示すフロー図である。以下では、図3及び図4を参照して、コアノード及びスレーブノードの構成及び動作について説明する。
FIG. 3 is a block diagram showing an example of the core node 21 and the slave node 41 according to the embodiment of the present invention. FIG. 4 is a flowchart showing operations of the core node 21 and the slave node 41 of FIG. Hereinafter, the configuration and operation of the core node and the slave node will be described with reference to FIGS. 3 and 4.
まず、図3(a)及び図4(a)を参照して、コアノードの構成について説明する。
First, the configuration of the core node will be described with reference to FIGS. 3 (a) and 4 (a).
図3(a)にあるように、コアノード21は、送信するパケットを格納する送信バッファ23と、受信したパケットを格納する受信バッファ25と、送信バッファ23及び受信バッファ25を制御するバッファ制御部27と、スレーブノードと通信を行う複数の通信部291、・・・29Nと、送信バッファ23に格納されたパケットから1つのパケットを送信準備パケットとして選択する送信準備パケット選択部31と、パケット送信基準が真である場合に送信可能割り込みイベントを発生するイベント発生部33と、通信部291、・・・、29Nの1つを選択して、選択した通信部に送信準備パケットを送信させる通信制御部35を備える。
As illustrated in FIG. 3A, the core node 21 includes a transmission buffer 23 that stores a packet to be transmitted, a reception buffer 25 that stores a received packet, and a buffer control unit 27 that controls the transmission buffer 23 and the reception buffer 25. A plurality of communication units 29 1 ,... 29 N that communicate with the slave node, a transmission preparation packet selection unit 31 that selects one packet from the packets stored in the transmission buffer 23 as a transmission preparation packet, and a packet Select one of the event generating unit 33 and the communication units 29 1 ,..., 29 N that generate a transmittable interrupt event when the transmission reference is true, and transmit a transmission preparation packet to the selected communication unit The communication control unit 35 is provided.
通信部291、・・・、29Nは、それぞれ異なるチャネルが割り当てられ、無線によりスレーブノードとの通信を行う無線機である。通信部291、・・・、29Nには、上り優先度と下り優先度という2種類の優先度が設定されている。通信部291、・・・、29Nは、この順番に、下り優先度が高いものは上り優先度が低く、上り優先度が高いものは下り優先度が低くなるように、上り優先度と下り優先度が正反対となるように設定されているものとする。以下では、通信部291が最も上り優先度が高くて最も下り優先度が低く、通信部292が次に上り優先度が高くて下り優先度が低く、順に、通信部29Nが最も上り優先度が低くて最も下り優先度が高いものとする。
The communication units 29 1 ,..., 29 N are wireless devices that are assigned different channels and communicate with the slave nodes wirelessly. Two types of priority, that is, uplink priority and downlink priority, are set in the communication units 29 1 ,..., 29 N. The communication units 29 1 ,..., 29 N are arranged in this order so that those having a high downlink priority have a low uplink priority and those having a high uplink priority have a low downlink priority. It is assumed that the downlink priority is set to be opposite. In the following, the communication unit 29 1 and most downlink priority is lower highest uplink priority is high, the communication unit 29 2 next uplink priority is higher downlink priority is low, in turn, the communication unit 29 N most upstream It is assumed that the priority is low and the downlink priority is the highest.
バッファ制御部27は、通信部291、・・・、29Nが受信したパケットを受信バッファ25に格納する。また、バッファ制御部27は、送信バッファ23に対し、例えば、コアノード21において発生したスレーブノード宛のパケットや、外部ネットワーク(図1のワイヤライン・コア・ネットワーク109参照)より受信したスレーブノードに対して送信されるべきパケットを格納する。なお、送信バッファ23に格納されるパケットは下りパケットであり、コアノードからスレーブノードに送信されるものである。
The buffer control unit 27 stores the packets received by the communication units 29 1 ,..., 29 N in the reception buffer 25. Further, the buffer control unit 27 responds to the transmission buffer 23 with respect to, for example, a packet addressed to the slave node generated in the core node 21 or a slave node received from an external network (see the wireline core network 109 in FIG. 1). Stores the packet to be transmitted. Note that the packet stored in the transmission buffer 23 is a downstream packet and is transmitted from the core node to the slave node.
送信準備パケット選択部31は、送信バッファ23に格納されたパケット群に送信優先順位を設定し、最も送信優先順位の高いパケットを次に送信されるパケットである送信準備パケットとして選択する。送信優先順位は、例えば、送信バッファ23に格納された時間が長いパケットが優先順位を高く設定してもよく(FIFO送信)、送信優先順位が一つ異なるパケット間で次伝送ノードが一致しないように設定してもよく(ラウンドロビン送信)、送信順位が一つ異なるパケット間で次伝送ノードが一致するように設定してもよい(集中伝送)。
The transmission preparation packet selection unit 31 sets a transmission priority for the packet group stored in the transmission buffer 23, and selects a packet with the highest transmission priority as a transmission preparation packet to be transmitted next. As for the transmission priority, for example, a packet stored in the transmission buffer 23 may have a high priority (FIFO transmission) so that the next transmission node does not match between packets having different transmission priorities. May be set (round robin transmission), or may be set so that the next transmission node matches between packets having different transmission orders (concentrated transmission).
イベント発生部33は、パケット送信基準が真である場合に送信可能割り込みイベントを発生する。パケット送信基準としては、例えば、送信バッファ23が空でないこととし、スレーブノードに対してパケットを積極的に送信するようにする。
The event generation unit 33 generates a transmittable interrupt event when the packet transmission standard is true. As a packet transmission standard, for example, the transmission buffer 23 is not empty, and packets are actively transmitted to the slave node.
通信制御部35は、イベント発生部33が送信可能割り込みイベントを発生した場合、下り優先度に従って1つの通信部を選択し、選択された通信部に対して、送信待機状態を経て送信準備パケットを送信させる。
When the event generating unit 33 generates a transmittable interrupt event, the communication control unit 35 selects one communication unit according to the downlink priority, and sends a transmission preparation packet to the selected communication unit through a transmission standby state. Send it.
通信制御部35の動作について、図4(a)を参照して、具体的に説明する。図4(a)は、図3(a)の通信制御部35の動作を示すフロー図である。
The operation of the communication control unit 35 will be specifically described with reference to FIG. FIG. 4A is a flowchart showing the operation of the communication control unit 35 in FIG.
通信制御部35は、まず、送信可能割り込みイベントが発生したか否かを判断する(ステップSTC1)。
The communication control unit 35 first determines whether or not a transmittable interrupt event has occurred (step STC1).
次に、通信制御部35は、イベントが発生した場合、下り優先度に基づいて通信部を選択する(ステップSTC2)。具体的には、送信バッファ23に格納されたパケットの数が所定の数PNTを超えない場合は、最も下り優先度の高い通信部29Nを選択する。送信バッファ23に格納されたパケットの数がPNTを超える場合には、例えば、通信部29N、29N-1、・・・、291、29N、29N-1、・・・のように、直前に選択した通信部が最も優先度の低い通信部291でないときは直前に選択した通信部の次に下り優先度の高い通信部を選択し、直前に選択した通信部が通信部291のときは最も下り優先度の高い通信部29Nを選択する。このように、通信制御部35は、下り優先度に従い、送信バッファ23の状態に応じたパケット選択基準により、通信部を選択する。
Next, when an event occurs, the communication control unit 35 selects a communication unit based on the downlink priority (step STC2). Specifically, when the number of packets stored in the transmission buffer 23 does not exceed a predetermined number PNT , the communication unit 29N having the highest downlink priority is selected. When the number of packets stored in the transmission buffer 23 exceeds PNT , for example, communication units 29 N , 29 N−1 ,..., 29 1 , 29 N , 29 N−1 ,. as such, selecting the next higher downlink priority communication section of the communication unit previously selected when the communication unit that was selected directly before is not the lowest priority communication unit 29 1, the communication unit is a communication that previously selected when the parts 29 1 to select the most downstream high priority communication section 29 N. As described above, the communication control unit 35 selects the communication unit according to the packet selection criterion corresponding to the state of the transmission buffer 23 according to the downlink priority.
次に、通信制御部35は、選択された通信部に対して、当該通信部上で直前にパケットを送信し終えた時刻から送信準備パケットを送信させる時刻までの時間が、例えば送信準備パケットの送信先となるスレーブノードや送信準備パケットのパケット長に応じて設定される送信周期となるように、送信待機状態を経させ(ステップSTC3)、その後に、選択された通信部に対して、送信準備パケットを送信させる(ステップSTC4)。そして、ステップSTC1の処理に戻る。
Next, the communication control unit 35, for the selected communication unit, the time from the time when the packet was transmitted immediately before on the communication unit to the time when the transmission preparation packet is transmitted is, for example, the transmission preparation packet A transmission standby state is set so that the transmission period is set according to the packet length of the slave node or transmission preparation packet as the transmission destination (step STC3), and then transmitted to the selected communication unit. A preparation packet is transmitted (step STC4). Then, the process returns to step STC1.
続いて、図3(b)及び図4(b)を参照して、スレーブノードの構成について説明する。
Subsequently, the configuration of the slave node will be described with reference to FIGS. 3B and 4B.
図3(b)にあるように、スレーブノード41は、図3(a)のコアノード21と同様に、送信するパケットを格納する送信バッファ43と、受信したパケットを格納する受信バッファ45と、送信バッファ43及び受信バッファ45を制御するバッファ制御部47と、スレーブノードと通信を行う複数の通信部491、・・・49Nと、送信バッファ43に格納されたパケットから1つのパケットを送信準備パケットとして選択する送信準備パケット選択部51と、パケット送信基準が真である場合に送信可能割り込みイベントを発生するイベント発生部53と、通信部491、・・・、49Nの1つを選択して、選択した通信部に送信準備パケットを送信させる通信制御部55を備える。
As shown in FIG. 3B, the slave node 41, like the core node 21 in FIG. 3A, transmits a transmission buffer 43 that stores a packet to be transmitted, a reception buffer 45 that stores a received packet, and a transmission Buffer control unit 47 that controls the buffer 43 and the reception buffer 45, a plurality of communication units 49 1 ,... 49 N that communicate with the slave nodes, and one packet prepared for transmission from the packets stored in the transmission buffer 43 Select one of transmission preparation packet selection unit 51 to be selected as a packet, event generation unit 53 that generates a transmittable interrupt event when the packet transmission reference is true, and communication units 49 1 ,..., 49 N The communication control unit 55 is configured to cause the selected communication unit to transmit a transmission preparation packet.
通信部491、・・・、49Nは、それぞれ異なるチャネルが割り当てられ、無線により他のノードとの通信を行う無線機である。通信部491、・・・、49Nには、通信部291、・・・、29Nと同様に、上り優先度と下り優先度が設定されている。
The communication units 49 1 ,..., 49 N are wireless devices that are assigned different channels and communicate with other nodes wirelessly. The communication unit 49 1, ..., the 49 N, the communication unit 29 1, ..., similarly to the 29 N, uplink priority and downlink priority is set.
バッファ制御部47は、通信部491、・・・、49Nが受信したパケットを受信バッファ45に格納する。また、バッファ制御部47は、送信バッファ43に対し、例えば、スレーブノード41で発生した他のノード宛のパケットや、他のスレーブノードから受信した他のスレーブノード宛のパケットを格納させる。送信バッファ43に格納されるパケットには、上りパケットと下りパケットが含まれる。
The buffer control unit 47 stores the packets received by the communication units 49 1 ,..., 49 N in the reception buffer 45. Further, the buffer control unit 47 causes the transmission buffer 43 to store, for example, packets addressed to other nodes generated in the slave node 41 and packets addressed to other slave nodes received from other slave nodes. The packets stored in the transmission buffer 43 include upstream packets and downstream packets.
送信準備パケット選択部51は、送信バッファ43に格納されたパケット群に送信優先順位を設定し、最も送信優先順位の高いパケットを送信準備パケットとして選択する。送信優先順位は、例えば、送信バッファ43に格納された時間が長いパケットが優先順位を高く設定する(FIFO送信)。
The transmission preparation packet selection unit 51 sets a transmission priority for the packet group stored in the transmission buffer 43, and selects a packet with the highest transmission priority as a transmission preparation packet. As for the transmission priority, for example, a packet stored for a long time in the transmission buffer 43 sets a high priority (FIFO transmission).
イベント発生部53は、パケット送信基準が真である場合に送信可能割り込みイベントを発生する。
The event generation unit 53 generates a transmittable interrupt event when the packet transmission standard is true.
パケット送信基準としては、例えば、送信バッファ43に新たなパケットが追加されたこととしてもよい(下り非同期IPT)。具体的には、他のスレーブノード若しくはコアノードからパケットを受信する場合、又は、当該スレーブノード内部でパケットが発生する場合である。
As a packet transmission standard, for example, a new packet may be added to the transmission buffer 43 (downlink asynchronous IPT). Specifically, it is a case where a packet is received from another slave node or a core node, or a case where a packet is generated inside the slave node.
また、パケット送信基準として、送信バッファ43に新たな下りパケットが追加されたこととしてもよい(下り同期IPT)。特に、下り同期とすることにより、さらに効率のよい中継伝送を達成することができる。すなわち、下り同期は、下り回線はコアノードがあたかもポーリングするような中継伝送が行われることに着目するものである。上り回線では、下り回線でIPTにより中継伝送される下りパケットをポーリング信号のごとく捉え、これに同期させて伝送する。この伝送により、中継パケットの衝突が回避され、さらに効率のよい中継伝送効率を達成することができる。ただし、下り同期では、下りパケットの受信がそれほどない場合に、スレーブノードに上りパケットが溜まる可能性がある。そのため、例えば、定期的に、コアノードから空の下りパケットをIPTにより伝送するようにしてもよく、また、他のノードからのパケットの受信を待たずに、イベント発生部53は、スレーブノードに一定数以上のパケットが溜まった場合には送信可能割り込みイベントを発生し、送信バッファ43のパケット送信が行われるようにしてもよい。
Also, as a packet transmission reference, a new downlink packet may be added to the transmission buffer 43 (downlink synchronization IPT). In particular, more efficient relay transmission can be achieved by using downlink synchronization. That is, downlink synchronization focuses on the fact that the downlink is relayed as if the core node is polling. In the uplink, a downlink packet relayed and transmitted by IPT in the downlink is regarded as a polling signal and transmitted in synchronization therewith. By this transmission, relay packet collision is avoided, and more efficient relay transmission efficiency can be achieved. However, in downlink synchronization, when there is not much downlink packet reception, there is a possibility that uplink packets will accumulate in the slave node. For this reason, for example, an empty downlink packet may be periodically transmitted from the core node by IPT, and the event generating unit 53 does not wait for reception of a packet from another node, and the slave node does not wait for reception of the packet. If more than a few packets accumulate, a transmittable interrupt event may be generated and packet transmission of the transmission buffer 43 may be performed.
通信制御部55は、イベント発生部53が送信可能割り込みイベントを発生した場合、送信準備パケットが上りパケットの場合には上り優先度に従って、送信準備パケットが下りパケットの場合には下り優先度に従って、1つの通信部を選択し、選択された通信部に対して送信準備パケットを送信させる。
When the event generating unit 53 generates a transmittable interrupt event, the communication control unit 55 follows the uplink priority when the transmission preparation packet is an uplink packet, and follows the downlink priority when the transmission preparation packet is a downlink packet. One communication unit is selected, and a transmission preparation packet is transmitted to the selected communication unit.
通信制御部55の動作について、図4(b)を参照して、具体的に説明する。図4(b)は、図3(b)の通信制御部55の動作を示すフロー図である。
The operation of the communication control unit 55 will be specifically described with reference to FIG. FIG. 4B is a flowchart showing the operation of the communication control unit 55 in FIG.
通信制御部55は、まず、送信可能割り込みイベントが発生したか否かを判断する(ステップSTS1)。
The communication control unit 55 first determines whether or not a transmittable interrupt event has occurred (step STS1).
次に、通信制御部35は、送信準備パケットが上りパケットか否かを判断する(ステップSTS2)。送信準備パケットが上りパケットである場合、通信制御部35は、図4のステップSTC2において説明したことと同様にして、上り優先度に従って通信部を選択する(ステップSTS3)。送信準備パケットが下りパケットである場合、通信制御部35は、図4のステップSTC2において説明したことと同様にして、下り優先度に従って通信部を選択する(ステップSTS4)。
Next, the communication control unit 35 determines whether or not the transmission preparation packet is an uplink packet (step STS2). When the transmission preparation packet is an uplink packet, the communication control unit 35 selects a communication unit according to the uplink priority in the same manner as described in step STC2 of FIG. 4 (step STS3). When the transmission preparation packet is a downlink packet, the communication control unit 35 selects a communication unit according to the downlink priority in the same manner as described in step STC2 of FIG. 4 (step STS4).
次に、通信制御部35は、選択された通信部に対して、通信待機状態を経ることなく、送信準備パケットを送信させる(ステップSTS5)。そして、ステップSTS1の処理に戻る。
Next, the communication control unit 35 causes the selected communication unit to transmit a transmission preparation packet without going through a communication standby state (step STS5). Then, the process returns to step STS1.
以上をまとめると、コアノード及びスレーブノードの動作は、次の表のようにまとめることができる。すなわち、上りパケットの送信はスレーブノードのみが関連するが、通信部の選択は上り優先度に従って行われ、送信可能割り込みイベントの発生により送信処理がなされる。他方、下りパケットの送信は、コアノードもスレーブノードも行う。通信部の選択は下り優先度に従って行われ、コアノードでは周期的間欠にパケットの送信が行われ、スレーブノードでは送信可能割り込みイベントの発生により送信処理がなされる。
In summary, the operations of the core node and slave node can be summarized as shown in the following table. That is, only the slave node is related to the transmission of the uplink packet, but the selection of the communication unit is performed according to the uplink priority, and the transmission process is performed by the occurrence of the transmittable interrupt event. On the other hand, transmission of the downlink packet is performed by both the core node and the slave node. The communication unit is selected according to the downlink priority. The core node periodically transmits packets, and the slave node performs transmission processing upon occurrence of a transmittable interrupt event.
なお、通信部291、・・・、29Nに割り当てられるチャネルに関して、上り優先度もしくは下り優先度が等しい通信部はすべてのノードにおいて同じ無線チャネルを割り当ててもよい(固定チャネル割り当て)。
In addition, regarding the channels allocated to the communication units 29 1 ,..., 29 N , the communication units having the same uplink priority or downlink priority may allocate the same radio channel in all nodes (fixed channel allocation).
また、スレーブノードの場合には各通信部は当該スレーブノードの中継先となる中継先ノードにおいて最も電波干渉を受けにくい無線チャネルを割り当て、上り優先度もしくは下り優先度が等しい無線機に割り当てられた無線チャネルが中継元ノードと中継先ノードとで異なる場合、中継先ノードでは当該ノードが送信するとき以外は中継元ノードの無線チャネルに合わせるようにしてもよい(ダイナミックチャネル選択)。特に、ダイナミックチャネル選択により、干渉をより一層軽減することができる。すなわち、ISMバンドの適用を前提とした場合、干渉は、自身のメッシュクラスタ内で発生する近隣の中継回線から発せられる干渉と、他の無線システムから発せられる干渉という2つの根源がある。各中継リンクに最も干渉の影響を受けにくいチャネルを動的に選択し、ISMバンドの下であってもロバストな中継伝送を実現することができる。IPTを前提としたダイナミックチャネル選択を行うことにより、マルチチャネルIPTとの相乗効果を発揮することができる。
In the case of a slave node, each communication unit is assigned a radio channel that is least susceptible to radio wave interference at the relay destination node that is the relay destination of the slave node, and is assigned to a radio device having the same uplink priority or downlink priority. When the radio channel is different between the relay source node and the relay destination node, the relay destination node may be adapted to the radio channel of the relay source node except when the node transmits (dynamic channel selection). In particular, interference can be further reduced by dynamic channel selection. That is, assuming application of the ISM band, there are two sources of interference: interference generated from a neighboring trunk line generated in its own mesh cluster and interference generated from another wireless system. Channels that are least susceptible to interference are dynamically selected for each relay link, and robust relay transmission can be realized even under the ISM band. By performing dynamic channel selection based on IPT, a synergistic effect with multi-channel IPT can be exhibited.
また、流れるトラフィックは、メッシュクラスタの外郭に位置するノードでは疎となる。例えば、下り回線ばかりしか伝送されない状況では、上り回線用に確保した車線はほとんど使われない。そのため、スレーブノード間では、使用されていない車線に反対方向のパケットを流すようにしてもよい(リンクborrowing)。
Also, the traffic that flows is sparse at nodes located outside the mesh cluster. For example, in a situation where only the downlink is transmitted, the lane reserved for the uplink is hardly used. Therefore, between the slave nodes, packets in the opposite direction may be sent to the unused lane (link borrowing).
続いて、図5~9を参照して、本願発明に関するシミュレーション結果を示し、本願発明の有効性について説明する。
Subsequently, referring to FIGS. 5 to 9, simulation results relating to the present invention will be shown, and the effectiveness of the present invention will be described.
図5は、本願発明のシミュレーションにおけるノードの配置を示す図である。シミュレーション緒元について説明する。コアノードは1個(図5において0番のもの)、スレーブノードは23個である。伝播路は、5mまでは伝播定数α=2であり、それ以上はα=3.5である(屋内環境モデル)。ルーティングは最小伝播損ルーティングである。シャドウイングは壁による減衰のみ(12dB)である。無線IFはIEEE802.11a(54Mbps)である。データパケットサイズは1500bytes、シミュレーション時間は180secである。トラフィックモデルは、UDPトラフィックのみであり、呼は基地局においてポアソン生起、1パケットバーストあたりのパケット数は対数正規分布に従う(Uplinkは平均3パケット、Downlinkは平均20パケットであり、上下総トラフィック比は1:10。)。IPTは、コアノードからの下り回線トラフィックにのみ適用する。
FIG. 5 is a diagram showing the arrangement of nodes in the simulation of the present invention. The simulation specifications will be explained. There are one core node (number 0 in FIG. 5) and 23 slave nodes. The propagation path has a propagation constant α = 2 up to 5 m and α = 3.5 beyond that (indoor environment model). Routing is minimum propagation loss routing. Shadowing is only wall attenuation (12 dB). The wireless IF is IEEE 802.11a (54 Mbps). The data packet size is 1500 bytes and the simulation time is 180 seconds. The traffic model is only UDP traffic, the call is generated by Poisson at the base station, the number of packets per packet burst follows a lognormal distribution (Uplink has an average of 3 packets, Downlink has an average of 20 packets, and the upper and lower total traffic ratio is 1:10.). IPT applies only to downlink traffic from the core node.
図6は、システムスループットについて、本願発明の実施例である下りリンク用チャネルにのみIPTを適用したもの(以下、「DL-IPT」という。)と、従来技術との比較を示す図である。比較の対象となる3つの従来技術は、一つが使用するチャネル(IF)が一つのみのもの(SingleCh。以下、「従来技術1」という。)、2つの無線IFを使用し、上り、下りリンクにそれぞれチャネルを割り当てたもの(DualCh;UL&DL。以下、「従来技術2」という。)、上り、下りの区別無くチャネルを使用するもの(DualCh;Mixed。以下、「従来技術3」という。)である。本願発明の実施例であるDL-IPTでは、下りリンク用チャネルにのみIPTを適用する。最小CW=7[slot time]、送信周期=0.5[msec]に設定する。ただし、キューに下りリンクのパケットがある程度溜まってきたら上りリンクのチャネルも使用する(リンクborrowing)。
FIG. 6 is a diagram showing a comparison between the system throughput and the prior art in which IPT is applied only to the downlink channel according to the embodiment of the present invention (hereinafter referred to as “DL-IPT”). The three prior arts to be compared are those in which only one channel (IF) is used (SingleCh; hereinafter referred to as “prior art 1”), and two radio IFs are used for uplink and downlink. Each channel is assigned a channel (DualCh; UL &DL; hereinafter referred to as “conventional technology 2”), and each channel is used without distinction between uplink and downlink (DualCh; Mixed; hereinafter referred to as “conventional technology 3”). It is. In DL-IPT which is an embodiment of the present invention, IPT is applied only to a downlink channel. Set minimum CW = 7 [slot time] and transmission cycle = 0.5 [msec]. However, when a certain amount of downlink packets are accumulated in the queue, the uplink channel is also used (link borrowing).
図6において、横軸は呼量であり、縦軸は合計スループットである。図5に示されているように、スループットは、従来技術1では高々約12Mbps、従来技術2では高々約13Mbpsである。従来技術3では、高々約24Mbpsであり、従来技術1や従来技術2に比較して約2倍となっている。それに対し、本願発明の実施例であるDL-IPTでは、約27Mbpsが達成されており、従来技術3と比較しても、約12%も改善されている。
In FIG. 6, the horizontal axis is the call volume, and the vertical axis is the total throughput. As shown in FIG. 5, the throughput is about 12 Mbps at the highest in the conventional technique 1 and about 13 Mbps at the highest in the conventional technique 2. In the prior art 3, it is at most about 24 Mbps, which is about twice that of the prior art 1 and the prior art 2. On the other hand, in the DL-IPT which is an embodiment of the present invention, about 27 Mbps is achieved, which is an improvement of about 12% compared with the prior art 3.
なお、上り回線におけるトラフィックが下り回線におけるトラフィックに比べて小さく、ほとんど空いている状態であるため、上り回線にも下り回線のトラフィックを流すことでシステムスループットは大幅に向上した。
Since the traffic on the uplink is smaller than the traffic on the downlink and is almost free, the system throughput is greatly improved by passing the downlink traffic on the uplink.
図7は、1パケットあたりの平均遅延について、本願発明の実施例であるDL-IPTと、従来技術との比較を示す図である。平均遅延は、パケットがキューに蓄えられてから最終宛先ノードへ届くまでの時間である。図6において、横軸は呼量であり、縦軸は平均遅延である。平均遅延が0.5[sec/Packet]を超えるときの呼量の値を比較すると、従来技術1では約12Mbps、従来技術2では約13Mbps、従来技術3では約24Mbpsである。それに対し、本願発明の実施例であるDL-IPTでは、約26Mbpsであり、従来技術と比較して、大幅に改善されている。
FIG. 7 is a diagram showing a comparison between DL-IPT, which is an embodiment of the present invention, and the prior art with respect to the average delay per packet. The average delay is the time from when a packet is stored in the queue until it reaches the final destination node. In FIG. 6, the horizontal axis is the call volume, and the vertical axis is the average delay. Comparing the value of call volume when the average delay exceeds 0.5 [sec / Packet], it is about 12 Mbps in the conventional technique 1, about 13 Mbps in the conventional technique 2, and about 24 Mbps in the conventional technique 3. On the other hand, in the DL-IPT which is an embodiment of the present invention, it is about 26 Mbps, which is a significant improvement over the prior art.
図8は、下り回線トラフィックにおけるパケットロス率について、本願発明の実施例であるDL-IPTと、従来技術との比較を示す図である。ここで、パケットロス率は、最大再送回数を超えて破棄されたバケット数を、受信に成功したパケット数と破棄されたパケット数を足したもので割って得られたものとする。図8において、横軸は呼量であり、縦軸はパケットロス率である。従来技術3では、低くとも0.02%以上あり、呼量が20Mbpsを超えると約0.05%程度にまで上昇している。それに対し、本願発明の実施例であるDL-IPTでは、0.01以下とほぼ0に近く、従来技術3と比較して、大幅に改善されている。
FIG. 8 is a diagram showing a comparison between the DL-IPT, which is an embodiment of the present invention, and the prior art regarding the packet loss rate in downlink traffic. Here, the packet loss rate is obtained by dividing the number of buckets discarded beyond the maximum number of retransmissions by the sum of the number of packets successfully received and the number of discarded packets. In FIG. 8, the horizontal axis represents the call volume, and the vertical axis represents the packet loss rate. In the prior art 3, it is 0.02% or more at the lowest, and increases to about 0.05% when the call volume exceeds 20 Mbps. On the other hand, in the DL-IPT which is an embodiment of the present invention, it is almost equal to 0, which is 0.01 or less, which is a significant improvement compared to the prior art 3.
図9は、上り回線トラフィックにおけるパケットロス率について、本願発明の実施例であるDL-IPTと、従来技術との比較を示す図である。図9において、横軸は呼量であり、縦軸はパケットロス率である。上り回線トラフィックに関しては、従来技術3が高くとも0.05%以下であるのに対し、本願発明の実施例であるDL-IPTでは、呼量が低いときには従来技術3と同様の値となっているものの、呼量の値が大きくなるにつれて0.08%付近にまで上昇している。
FIG. 9 is a diagram showing a comparison between the DL-IPT, which is an embodiment of the present invention, and the prior art with respect to the packet loss rate in uplink traffic. In FIG. 9, the horizontal axis represents the call volume, and the vertical axis represents the packet loss rate. With respect to uplink traffic, the conventional technique 3 is 0.05% or less at most, whereas the DL-IPT according to the embodiment of the present invention has the same value as the conventional technique 3 when the call volume is low. However, it increases to around 0.08% as the call volume increases.
なお、上り回線を使わないDL-IPTのみの適用では、最大で16Mbpsの改善が得られている。同じ条件の従来技術に対しては、20%程度、改善されている。
It should be noted that an improvement of up to 16 Mbps has been obtained by applying only DL-IPT without using an uplink. Compared to the prior art under the same conditions, it is improved by about 20%.
Claims (15)
- 1つのコアノードと複数のスレーブノードを含むネットワークシステムにおいて、
前記各スレーブノードは、
前記コアノードから他のスレーブノードに対して送信されたパケットである下りパケット、及び、スレーブノードから前記コアノードに対して送信されたパケットである上りパケットを格納する送信バッファと、
他のノードからパケットを受信し、及び、他のノードに対して前記送信バッファに格納されたパケットを送信し、並びに、2種類の優先度である下り優先度及び上り優先度が設定された複数の通信手段と、
前記送信バッファに格納されたパケットから送信準備パケットを選択する送信準備パケット選択手段と、
前記送信準備パケットが前記下りパケットであれば前記下り優先度に従って、又は、前記送信準備パケットが前記上りパケットであれば前記上り優先度に従って、1つの通信手段を選択し、選択された通信手段に対して前記送信準備パケットを送信させる通信制御手段を備え、
前記コアノードは、
パケットを格納する送信バッファと、
スレーブノードからパケットを受信し、及び、スレーブノードに対して前記送信バッファに格納されたパケットを送信し、並びに、2種類の優先度である下り優先度及び上り優先度が設定された複数の通信手段と、
前記送信バッファに格納されたパケットから送信準備パケットを選択する送信準備パケット選択手段と、
前記下り優先度に従って1つの通信手段を選択し、選択された通信手段に対して、送信待機状態を経て前記送信準備パケットを送信させることにより、当該通信手段上で直前にパケットを送信し終えた時刻から前記送信準備パケットを送信させる時刻までの時間を所定の時間とする通信制御手段を備える
ネットワークシステム。 In a network system including one core node and a plurality of slave nodes,
Each slave node is
A transmission buffer that stores a downstream packet that is a packet transmitted from the core node to another slave node, and an upstream packet that is a packet transmitted from the slave node to the core node;
A plurality of packets that receive packets from other nodes, transmit packets stored in the transmission buffer to other nodes, and have two types of priority, downlink priority and uplink priority. Communication means of
Transmission preparation packet selection means for selecting a transmission preparation packet from the packets stored in the transmission buffer;
If the transmission preparation packet is the downlink packet, select one communication means according to the downlink priority, or if the transmission preparation packet is the uplink packet, select one communication means according to the selected communication means. Communication control means for transmitting the transmission preparation packet to,
The core node is
A send buffer to store the packet;
A plurality of communications that receive a packet from a slave node, transmit a packet stored in the transmission buffer to the slave node, and have two types of priorities, a downlink priority and an uplink priority. Means,
Transmission preparation packet selection means for selecting a transmission preparation packet from the packets stored in the transmission buffer;
By selecting one communication means according to the downlink priority and causing the selected communication means to transmit the transmission preparation packet through a transmission standby state, the packet has been transmitted immediately before on the communication means. A network system comprising communication control means for setting a time from a time to a time for transmitting the transmission preparation packet to a predetermined time. - 前記各スレーブノードは、下りパケットを受信した場合にイベントを発生するイベント発生手段を備え、
前記スレーブノードの前記通信制御手段は、前記スレーブノードの前記イベント発生手段によりイベントが発生した場合に1つの通信手段を選択する、
請求項1記載のネットワークシステム。 Each slave node includes event generation means for generating an event when a downstream packet is received,
The communication control means of the slave node selects one communication means when an event occurs by the event generation means of the slave node;
The network system according to claim 1. - 前記コアノードは、スレーブノードに対して、定期的にパケットを送信する、
請求項2記載のネットワークシステム。 The core node periodically transmits packets to the slave node.
The network system according to claim 2. - 前記イベント発生手段は、前記送信バッファに所定の数以上のパケットが格納されていた場合にイベントを発生する、
請求項2又は3記載のネットワークシステム。 The event generation means generates an event when a predetermined number or more packets are stored in the transmission buffer.
The network system according to claim 2 or 3. - 前記各スレーブノードは、前記送信バッファに新たなパケットが追加された場合にイベントを発生するイベント発生手段を備え、
前記スレーブノードの前記通信制御手段は、前記スレーブノードの前記イベント発生手段によりイベントが発生した場合に1つの通信手段を選択する、
請求項1記載のネットワークシステム。 Each slave node includes event generation means for generating an event when a new packet is added to the transmission buffer,
The communication control means of the slave node selects one communication means when an event occurs by the event generation means of the slave node.
The network system according to claim 1. - 前記上り優先度の最も高い通信手段と前記下り優先度の最も高い通信手段とは異なる、請求項1から5のいずれかに記載のネットワークシステム。 6. The network system according to claim 1, wherein the communication means having the highest uplink priority is different from the communication means having the highest downlink priority.
- 前記コアノードの前記通信制御手段は、当該通信手段上で直前にパケットを送信し終えた時刻から前記送信準備パケットを送信させる時刻までの時間を、前記送信準備パケットの送信先となるスレーブノード及び前記送信準備パケットのパケット長の少なくとも一方に応じて設定される送信周期とする、
請求項1から6のいずれかに記載のネットワークシステム。 The communication control means of the core node includes a slave node that is a transmission destination of the transmission preparation packet and a time from a time at which the packet is transmitted immediately before on the communication means to a time at which the transmission preparation packet is transmitted; The transmission cycle is set according to at least one of the packet lengths of the transmission preparation packets.
The network system according to claim 1. - 前記コアノード及び前記スレーブノードの少なくとも一方の前記通信制御手段は、
前記送信バッファに格納されたパケットの数が所定の数PNTを超えない場合、最も優先度の高い通信手段を選択し、
送信バッファに格納されたパケットの数がPNTを超える場合、
直前に選択した通信手段が最も優先度の低い通信手段ではないときは次に優先順位の高い通信手段を選択し、
直前に選択した通信手段が最も優先度の低い通信手段であるときは最も優先度の高い通信手段を選択する、
請求項1から7のいずれかに記載のネットワークシステム。 The communication control means of at least one of the core node and the slave node is:
If the number of packets stored in the transmission buffer does not exceed a predetermined number PNT , select the communication means with the highest priority,
If the number of stored in the transmission buffer packet exceeds P NT,
When the communication means selected immediately before is not the communication means with the lowest priority, select the communication means with the next highest priority,
When the communication means selected immediately before is the communication means with the lowest priority, the communication means with the highest priority is selected.
The network system according to claim 1. - 前記コアノードの前記送信準備パケット選択手段は、前記送信バッファに格納されたパケットに対して送信優先順位を設定し、送信優先順位の最も高いパケットを送信準備パケットとして選択するものであり、
前記送信優先順位は、
前記送信バッファに格納された時間が長いパケットが高くなるように設定されるか、
前記送信優先順位が一つ異なるパケット間で、パケットを中継伝送する場合に次に中継すべきノードである次伝送ノードが一致するように設定されるか、又は、
前記送信優先順位が一つ異なるパケット間で次伝送ノードが一致しないように設定される、
請求項1から8のいずれかに記載のネットワークシステム。 The transmission preparation packet selection means of the core node sets a transmission priority for the packet stored in the transmission buffer, and selects a packet with the highest transmission priority as a transmission preparation packet,
The transmission priority is
The packet stored in the transmission buffer is set to be high for a long time, or
When the packet is relayed and transmitted between packets having different transmission priorities, the next transmission node that is the node to be relayed next is set to match, or
The transmission priority is set so that the next transmission node does not match between packets with different transmission priorities.
The network system according to claim 1. - 前記複数の通信手段は無線通信により他のノードとパケットの送受信を行うものであり、
前記複数の通信手段には、それぞれ異なる無線チャネルが割り当てられ、
前記ネットワーク上において、上り優先度又は下り優先度が同一の通信手段に割り当てられる前記無線チャネルは同一である、
請求項1から9のいずれかに記載のネットワークシステム。 The plurality of communication means perform packet transmission / reception with other nodes by wireless communication,
Each of the plurality of communication means is assigned a different radio channel,
On the network, the radio channel assigned to the communication means having the same uplink priority or downlink priority is the same.
The network system according to claim 1. - 前記複数の通信手段は無線通信により他のノードとパケットの送受信を行うものであり、
前記複数の通信手段には、それぞれ、干渉受信レベルに基づいて異なる無線チャネルが割り当てられる、
請求項1から9のいずれかに記載のネットワークシステム。 The plurality of communication means perform packet transmission / reception with other nodes by wireless communication,
Each of the plurality of communication means is assigned a different radio channel based on an interference reception level.
The network system according to claim 1. - ネットワーク上の他のノードに対して送信準備パケットを送信するノードであって、
2種類の優先度である下り優先度及び上り優先度が設定された複数の通信手段と、
前記下り優先度又は前記上り優先度に従って前記複数の通信手段から1つの通信手段を選択し、選択された通信手段に対して前記送信準備パケットを送信させる通信制御手段
を備え、
前記通信制御手段は、
当該ノードがスレーブノードの場合には、
前記送信準備パケットの送信元がコアノードであるときは前記下り優先度に従って1つの通信手段を選択して前記送信準備パケットを送信させ、
前記送信準備パケットの送信先が前記コアノードであるときは前記上り優先度に従って1つの通信手段を選択して前記送信準備パケットを送信させ、
当該ノードがコアノードの場合には、前記下り優先度に従って前記複数の通信手段から1つの通信手段を選択し、送信待機状態を経て前記送信準備パケットを送信させることにより、当該通信手段上で直前にパケットを送信し終えた時刻から前記送信準備パケットを送信させる時刻までの時間を所定の時間とする、
ノード。 A node that transmits a transmission preparation packet to another node on the network,
A plurality of communication means in which a downlink priority and an uplink priority, which are two types of priorities, are set;
A communication control unit that selects one communication unit from the plurality of communication units according to the downlink priority or the uplink priority, and causes the selected communication unit to transmit the transmission preparation packet;
The communication control means includes
If the node is a slave node,
When a transmission source of the transmission preparation packet is a core node, select one communication means according to the downlink priority to transmit the transmission preparation packet,
When the transmission destination of the transmission preparation packet is the core node, according to the uplink priority, select one communication means to transmit the transmission preparation packet,
If the node is a core node, one communication unit is selected from the plurality of communication units in accordance with the downlink priority, and the transmission preparation packet is transmitted through the transmission standby state. A predetermined time is a time from a time at which a packet is transmitted to a time at which the transmission preparation packet is transmitted.
node. - 1つのコアノードと複数のスレーブノードを含むネットワークにおけるパケットフォワーディング方法であって、
前記コアノード及び前記各スレーブノードは、
他のノードと通信をするための複数の通信手段と、
前記複数の通信手段に設定された2種類の優先度である上り優先度及び下り優先度のいずれかに従って前記複数の通信手段の1つを選択し、選択した通信手段に対してパケットを送信させる通信制御手段
を備え、
前記コアノードから前記スレーブノードにパケットを中継転送する場合、
前記コアノードの通信制御手段が、下り優先度に従って前記複数の通信手段のいずれかを選択し、選択した通信手段に対して中継転送先のスレーブノードに送信待機状態を経て当該パケットを送信させ、
前記パケットを受信したスレーブノードの通信制御手段は、当該パケットの送信先が他のスレーブノードである場合には、下り優先度に従って前記複数の通信手段の1つを選択し、選択した通信手段に対して中継転送先のスレーブノードに当該パケットを送信させ、
前記スレーブノードから前記コアノードにパケットを中継転送する場合、
前記スレーブノードの通信制御手段が、上り優先度に従って前記複数の通信手段の1つを選択し、選択した通信手段に対して当該パケットを送信させる、
パケットフォワーディング方法。 A packet forwarding method in a network including one core node and a plurality of slave nodes,
The core node and each slave node are
A plurality of communication means for communicating with other nodes;
Select one of the plurality of communication means according to one of the two types of priorities set to the plurality of communication means, that is, the uplink priority and the downlink priority, and cause the selected communication means to transmit a packet. Comprising communication control means,
When relaying a packet from the core node to the slave node,
The communication control unit of the core node selects one of the plurality of communication units according to the downlink priority, and causes the selected communication unit to transmit the packet via a transmission standby state to the slave node of the relay transfer destination,
The communication control unit of the slave node that has received the packet selects one of the plurality of communication units according to the downlink priority when the transmission destination of the packet is another slave node, and selects the selected communication unit. On the other hand, send the packet to the slave node of the relay transfer destination,
When relaying a packet from the slave node to the core node,
The slave node communication control means selects one of the plurality of communication means according to the uplink priority, and causes the selected communication means to transmit the packet.
Packet forwarding method. - コンピュータを、請求項12記載の通信制御手段として機能させるためのプログラム。 A program for causing a computer to function as the communication control means according to claim 12.
- 請求項14記載のプログラムを記録する記録媒体。 A recording medium for recording the program according to claim 14.
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JP6580462B2 (en) | 2015-11-02 | 2019-09-25 | PicoCELA株式会社 | Network system, node, frame communication method and program |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0946753A (en) * | 1995-08-01 | 1997-02-14 | Toshiba Corp | Mobile communication method and mobile communication equipment |
JP2005079985A (en) * | 2003-09-01 | 2005-03-24 | Sony Corp | Wireless communication system, wireless communication apparatus and wireless communication method, and computer program |
JP2005143046A (en) | 2003-11-10 | 2005-06-02 | Sangaku Renkei Kiko Kyushu:Kk | Packet transmission method in wireless multi-hop network |
JP2005303828A (en) * | 2004-04-14 | 2005-10-27 | Ntt Docomo Inc | Wireless bridge, wireless communication system, and method of controlling resource allocation to packet transfer path |
JP2006157501A (en) | 2004-11-30 | 2006-06-15 | Kyushu Univ | Method of multiplexing two-way incoming and outgoing packet in radio multihop network with intermittent periodic transmit applied thereto |
JP2006319787A (en) | 2005-05-13 | 2006-11-24 | Kyushu Univ | Multistage radio relay method |
JP2006352896A (en) * | 2006-07-07 | 2006-12-28 | Toshiba Corp | Wireless communication apparatus |
JP2007158504A (en) * | 2005-12-01 | 2007-06-21 | Sony Corp | Wireless communication apparatus and program |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5313620A (en) * | 1989-04-06 | 1994-05-17 | Bell Communications Research, Inc. | Selective receiver for each processor in a multiple processor system |
JP3595778B2 (en) * | 2000-06-28 | 2004-12-02 | 松下電器産業株式会社 | Base station apparatus and channel allocation method |
US7002910B2 (en) * | 2000-10-30 | 2006-02-21 | The Regents Of The University Of California | Receiver-initiated channel-hopping (RICH) method for wireless communication networks |
US7149204B2 (en) * | 2001-06-20 | 2006-12-12 | Matsushita Electric Industrial Co., Ltd. | Base station device and channel assigning method |
JP3898965B2 (en) * | 2002-03-06 | 2007-03-28 | 株式会社エヌ・ティ・ティ・ドコモ | Radio resource allocation method and base station |
JP2006186905A (en) * | 2004-12-28 | 2006-07-13 | Advanced Telecommunication Research Institute International | Radio communication system |
WO2007060545A2 (en) * | 2005-05-26 | 2007-05-31 | Nokia Corporation | Traffic prioritization techniques for wireless networks |
JP2007235871A (en) * | 2006-03-03 | 2007-09-13 | Advanced Telecommunication Research Institute International | Wireless device and wireless network system using it |
US8072925B2 (en) * | 2006-03-08 | 2011-12-06 | Oki Electric Industry Co., Ltd. | Multi-hop wireless network system |
US8213344B2 (en) * | 2007-08-07 | 2012-07-03 | Intel Corporation | Method and apparatus for antenna allocation on a multi-radio platform |
-
2008
- 2008-01-29 JP JP2008018337A patent/JP5515072B2/en active Active
-
2009
- 2009-01-23 TW TW098102695A patent/TWI457034B/en active
- 2009-01-28 WO PCT/JP2009/051348 patent/WO2009096423A1/en active Application Filing
- 2009-01-28 US US12/864,332 patent/US8526365B2/en active Active
- 2009-01-28 EP EP09705079.3A patent/EP2242326B1/en active Active
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0946753A (en) * | 1995-08-01 | 1997-02-14 | Toshiba Corp | Mobile communication method and mobile communication equipment |
JP2005079985A (en) * | 2003-09-01 | 2005-03-24 | Sony Corp | Wireless communication system, wireless communication apparatus and wireless communication method, and computer program |
JP2005143046A (en) | 2003-11-10 | 2005-06-02 | Sangaku Renkei Kiko Kyushu:Kk | Packet transmission method in wireless multi-hop network |
JP2005303828A (en) * | 2004-04-14 | 2005-10-27 | Ntt Docomo Inc | Wireless bridge, wireless communication system, and method of controlling resource allocation to packet transfer path |
JP2006157501A (en) | 2004-11-30 | 2006-06-15 | Kyushu Univ | Method of multiplexing two-way incoming and outgoing packet in radio multihop network with intermittent periodic transmit applied thereto |
JP2006319787A (en) | 2005-05-13 | 2006-11-24 | Kyushu Univ | Multistage radio relay method |
JP2007158504A (en) * | 2005-12-01 | 2007-06-21 | Sony Corp | Wireless communication apparatus and program |
JP2006352896A (en) * | 2006-07-07 | 2006-12-28 | Toshiba Corp | Wireless communication apparatus |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102111897A (en) * | 2010-12-15 | 2011-06-29 | 西安交通大学 | Method for realizing polarization-diversity-based directional cognitive medium access control (MAC) protocol |
CN102111897B (en) * | 2010-12-15 | 2014-04-23 | 西安交通大学 | Method for realizing polarization-diversity-based directional cognitive medium access control (MAC) protocol |
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